Section 2

Study and characterization of the time course of drug liberation, absorption, distribution, metabolism and excretion.

Chemical Kinetics

Study of chemical processes and rates of reactions or processes.

Pharmacokinetic Models

Hypothesis that utilize mathematical terms to quantitatively describe relationships in biological processes in the body.

Compartment Model

Empirical Model

Compartment Model

Describes the fate of a drug in the body, depicted as an entity divided into compartments.

Compartment Model

Most widely used approach to pharmacokinetic characterization of drug.

Compartment Model

Type of model that interpolate the experimental data and allow on empirical formula to estimate drug concentration with time.

Compartment

Group of tissues with similar blood flow and drug affinity.

Rate Constant

Used to represent rate of entry into and exit from compartment.

Mammillary Model

Consists of 1 or more peripheral compartments connected to the central compartment.

Mammillary Model

Most commonly used compartment model.

One Compartment Open Model

Aka Instantaneous Distribution Model

One Compartment Open Model

Simplest model

One Compartment Open Model

Generally used to describe plasma levels following the administration of a single dose.

One Compartment Open Model

In this model, the rate of absorption is neglected in calculations.

Elimination

Metabolism and excretion

Elimination

It is a first -order process with first-order rate constant.

Elimination Rate Constant

It represents the sum of each rate constant of metabolism and excretion.

Drug in the Body (DB)

Computed via first-order process.

Apparent Volume of Distribution

Represents a volume that must be considered in estimating the amount of drug in the body from the concentration of drug found in the sampling compartment blood samples are collected at periodic intervals and the plasma portion of blood is analyzed for their drug concentrations.

Volume of Distribution

Determined by extrapolating the value of initial concentration (𝐶𝑂) in 𝑃 a given set of data.

Two Compartment Model

Drug appears to distribute instantaneously throughout a central compartment but more slowly and a at a single finite rate to a peripheral compartment.

Three Compartment Model

Drug is distributed most rapidly to a highly perfused central compartment, less rapidly to the second or tissue compartment, and very slowly to the third or deep tissue compartment, containing such poorly perfused tissue as bone and fat.

- Same active ingredient(s) - Same dosage form and route of administration - They are identical in strength or concentration

PHARMACEUTICAL ALTERNATIVES

Same therapeutic moiety, but are different salts, esters, or complexes of that moiety, or are different dosage forms or strengths.

THERAPEUTIC EQUIVALENTS

Pharmaceutical equivalents that have the same clinical effect and safety profile when administered to patients.

THERAPEUTIC ALTERNATIVES

Different drug but safe clinical effect.

BIOAVAILABILITY AND BIOEQUIVALENCE

Evaluate the clinical efficacy of different dosage forms or products made by different manufacturers.

BIOPHARMACEUTICS CLASSIFICATION SYSTEM (BCS)

Provides a of oral immediate release (IR) drug products by classifying drug compounds based on their SOLUBILITY related to dose and INTESTINAL PERMEABILITY in combination with the dissolution properties of the dosage form.

BIOPHARMACEUTICS DRUG DISPOSITION CLASSIFICATION SYSTEM (BDDCS)

Modified version of bcs

BIOPHARMACEUTICS DRUG DISPOSITION CLASSIFICATION SYSTEM (BDDCS)

Useful in predicting overall drug disposition, including routes of drug elimination and the effects of efflux and absorptive transporters on oral drug absorption; when transporter-enzyme interplay will yield clinically significant effects (e.g., low bioavailability and drug-drug interactions); the direction, mechanism, and importance of food effects; and transporter effects on post absorption systemic drug concentrations following oral and intravenous dosing.

BIOPHARMACEUTICS DRUG DISPOSITION CLASSIFICATION SYSTEM (BDDCS)

Well supported by experimental data on the effect of transporter inhibition and induction on drug metabolism

BIOPHARMACEUTICS DRUG DISPOSITION CLASSIFICATION SYSTEM (BDDCS)

Uses elimination criteria, may expand the number of class 1 drugs eligible for a waiver of in vivo bioequivalence studies and provide predictability of drug disposition profiles for classes 2, 3, and 4 compounds.